Department of Homeland Security Management Directive System 3150.1: Noncareer and Limited Senior Executive Service Employment [open pdf - 80KB]
"This directive establishes Department of Homeland Security (DHS) policy, procedures, and requirements for noncareer and limited Senior Executive Service (SES) employment, consistent with the requirements of subchapter VIII of chapter 33 of title 5 United States Code and Subpart F of 5 CFR [Code of Federal Regulations] Part 317."
Department of Homeland Security Management Directive System MD No. 3150.1
United States. Dept. of Homeland Security: http://www.dhs.gov/